The flow parts of slurry pump mainly include impeller, pressurized water chamber (jacket), guard plate, auxiliary impeller, water inlet pipe, water outlet pipe and axle sleeve with packing seal, etc., among which the wear degree of main flow parts such as impeller, pressurized water chamber (jacket) and guard plate is very serious, which is often needed to be replaced.
Through the wear analysis and research of a large number of slurry pump flow components, it is found that different parts of the pump wear, due to two-phase flow characteristics and slurry pump material surface structure characteristics change, the surface of the damaged surface presents different appearance morphology.
According to the wear pattern of slurry pump, the macroscopic wear pattern can be divided into general wear and local wear.
I. general wear and tear
Definition: abrasion caused by a fluid flow with particles in the pump that washes over the surface of the flow piece.
Generally, the surface of the worn material presents a corrugated scour trace of roughly the same depth, which can clearly reproduce the movement direction of the particles.
This kind of corrugated erosion is easy to occur on the inner surface of the inlet pipe and outlet pipe of the slurry pump, the outer edge of the jacket flow passage, most of the surface of the front guard and rear guard plate, most of the surface of the impeller blade of the slurry pump and the surface of the rear cover plate.
When the flow components have large and flat flow surfaces, the wavy general wear marks often develop in the form of fish-scale pits.
2. Local wear
Definition: severe local wear of materials occurring during general wear.
Generally, the impeller blade of slurry pump impeller inlet, outlet, front and rear guard plate near the impeller outside diameter, pressure chamber (double-layer structure slurry pump also known as jacket) of the tongue and other parts prone to local wear.
Local wear is usually caused by deterioration of the flow state near the surface of the overcurrent.
The main areas prone to flow deterioration are: large-scale flow separation caused by improper hydraulic design, the junction of the inner surface of the structure of the over-flow piece, the unlevel surface of the over-flow piece, and the wall surface of the material surface layer and sub-surface layer with casting defects.
Slurry pump operation for a period of time, the local wear performance is deep groove, hole or pit, can further develop to perforation, fracture, parts failure and scrap.
Compared with the general wear and tear, the development of local wear is much faster, damage to the material is more serious, so to improve the wear of slurry pump, main is to improve the flow conditions inside the pump, as far as possible to reduce the flow of partial abrasion, the requirements on the surface of the casting sand holes, no pit, must try to smooth, my company's slurry pump casting blank film figure is as follows:
In the slurry pump over - flow parts of the surface, sometimes both general wear, and local wear.
The wall of the pressurized water chamber not only presents a general wear area (most of the areas are fish-scale pit shaped wear marks left by slurry erosion), but also has an obvious local wear area (deep wear grooves and holes on the wall of the pressurized water chamber).
The wear marks on the surface of the slurry pump fender show that the local wear characteristics of the outer edge of the fender and the fitting surface of the pressurized water chamber (jacket) are very obvious.The rest of the wear is very light and uniform, showing a general wear characteristics.